This invention relates in general to prosthetic devices and more particularly to an improved mandibular prosthesis for replacing all or part of a defective or damaged jawbone.
In the past, the mandibular prostheses that have been available have not been altogether satisfactory. Typically, nuts and bolts are used to fasten the prostheses in place on the mandible, and this results in projections which cause discomfort and possible tissue damage in the patient. Slotting of the bone and the use of templates and wrenches are often required. In addition, the nuts tend to work loose in time and thereby detract from the integrity of the implanted structure. Existing mandibular prostheses have also been difficult to surgically implant, primarily because of their bulky nature and the difficulty involved in handling them. Perhaps even more importantly, the fastening systems that have been used are unable to stabilize the implanted structure securely in place. As a consequence, bone grafts are subjected to atrophy and other adverse effects that can in turn create problems in the facial tissues and other nearby tissues.
U.S. Pat. No. 3,720,959 to Hahn discloses a prosthesis that is constructed of malleable mesh material. This device is not only complicated and expensive to manufacture, but it also lacks structural strength and is fastened to the mandible in a less than satisfactory manner. The attachment of a bone graft to the Hahn device is difficult if not impossible.
The present invention is directed to an improved mandibular prosthesis which can be used in the replacement or reconstruction of virtually any part of the mandible. The prosthesis is characterized by a bifurcated structure presenting a pair of metal strips which are placed on opposite sides of a mandibular bone stump that remains on one side of the damaged area of the mandible. The metal strips are provided with alternating threaded and non-threaded holes, and the threaded holes on each strip are aligned with non-threaded holes in the other strip so that screws can be extended between the strips from either side. This makes the prosthesis reversible and allows it to be used on either side of the mandible.
It is an important object of the invention to provide a mandibular prosthesis that can be surgically implanted more quickly and easily than the prostheses that have been available in the past.
Another important object of the invention is to provide a mandibular prosthesis which is improved as to its structural integrity and which is secured in place with greater stability and lateral to medial holding power than is achieved with existing prostheses.
A further object of the invention is to provide a mandibular prosthesis which is constructed in a manner permitting it to be "custom tailored" to replace virtually any part of a damaged mandible.
An additional object of the invention is to provide a mandibular prosthesis that is constructed and fastened in a manner to avoid presenting any projections which can cause significant discomfort or damage to the facial tissue.
Still another object of the invention is to provide a mandibular prosthesis that is reversible so that it can be fitted on either side of the mandible.
Yet another object of the invention is to provide a mandibular prosthesis which is constructed simply and economically and which allows the jaw to function in a normal fashion for an extended period of time.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.